Injection molding machine

ABSTRACT

A plastic injection molding machine has a rotary indexing table and means supporting a stationary vertical standard which passes through a bore in the center of the table. A rotary fluid manifold is positioned concentrically about the standard and includes a pair of tubular sleeves having means between them defining axially spaced annular delivery and return passages. The outer sleeve is mounted on the rotary table for rotation therewith and the inner sleeve is keyed to the support standard. The manifold is provided with delivery and return bores in the inner sleeve which communicate with their respective passages and a plurality of outlets from the delivery passage and a plurality of inlets to the return passage to provide for rotary circulation of fluid through a plurality of mold parts spaced about the periphery of the indexing table. The vertical standard adds stability to the rotary table, and the manifold and standard cooperate to permit distribution of fluid to mold parts irrespective of their position on the table.

United States Patent Trueblood 1 1 May9, 1972 [54] INJECTION MOLDINGMACHINE [72] Inventor:

[52] US. Cl ..425/243, 165/86, 164/326,

425/246 [51] Int. Cl. ..B29c 3/02 [58] Field ofSearch ..18/20 B, 20 C,20 H, 20 R,

18/20 S, 20 T, 26 RR, 30 NA, 30 NZ, 30 PR, DIG. 9, 20 RR, 30 PM, 30 PO;25/99, 100, 80, 81; 165/86; 137/580; 164/326-328 {56] References CitedUNITED STATES PATENTS 2,828,508 4/1958 Labarre ..18/20 I X 2,064,62412/1936 Napier ..18/20 S 2,325,348 7/1943 Tucker ..18/20 5 2,304,80612/1942 Di Cosmo... 18/20 T X 3,364,523 1/1968 Schippers... ..18/l2 SZ3,091,809 6/1963 Trueb1ood.. 18/20 C UX 2,325,119 7/1943 Flowers..18/20S 1,969,323 8/1934 Person..... 18/20 RR 3,365,748 1/1968Cote..... 18/20 B X 2,117,400 5/1938 Cobb ..18/2O C 2,155,316 4/1939Lauterbach .....18/20 T 3,200,451 8/1965 Worswick ..l64/326 X 1,492,0174/1924 Candler 164/327 2,333,056 10/1943 Thoreson et al. ..18/20 H XFOREIGN PATENTS OR APPLICATIONS 1,204,772 1959 France 1 37/5 80 OTHERPUBLICATIONS German Printed Specification 1966 Germany Gill PrimaryExaminer-J. Spencer Overholser Assistant Examiner- De Walden W. JonesAttorney-Marechal, Biebel, French & Bugg [57] ABSTRACT A plasticinjection molding machine has a rotary indexing table and meanssupporting a stationary vertical standard which passes through a bore inthe center of the tablev A rotary fluid manifold is positionedconcentrically about the standard and includes a pair of tubular sleeveshaving means between them defining axially spaced annular delivery andreturn passages. The outer sleeve is mounted on the rotary table forrotation therewith and the inner sleeve is keyed to the supportstandard. The manifold is provided with delivery and return bores in theinner sleeve which communicate with their respective passages and aplurality of outlets from the delivery passage and a plurality of inletsto the return passage to provide for rotary circulation of fluid througha plurality of mold parts spaced about the periphery of the indexingtable. The vertical standard adds stability to the rotary table, and themanifold and standard cooperate to permit distribution of fluid to moldparts irrespective of their position on the table.

4 Claims, 3 Drawing Figures PATENTEDMAY 9 I972 INVENTOR RAYMOND LEETRUEBLOOD BY 2 g I A mi/v5?? INJECTION MOLDING MACHINE BACKGROUND OF THEINVENTION Plastic injection molding machines of the type described in E.D. Trueblood U.S. Pat. No. 3,309,739, issued Mar. 21, 1967, include abolster head and a movable table. When such a machine is provided with arotary index table, the bolster head carries a vertically reciprocatingupper mold part which selectively engages one of a plurality of bottommold parts positioned around the periphery of the table. During thisoperation the other bottom mold parts areaccessible for cooling,stripping and loading by inserting into the mold cavity any specialparts for the finished article.

In order to obtain uniform and quality products, such as electricalplug-in connectors on the ends of wires or the like, it is imperativethat the upper and bottom mold parts come together with precisealignment so that the parts will form pressure seals before the plasticis injected under pressure, and thereby prevent plastic from seeping outbetween the parts. One of the problems encountered is that when theforce of the upper mold part is exerted on the periphery of the indexingtable, there is a tendency for the table to deflect under the highpressures and to cause slight breaks in the seal between the parts. I

A clear need has been presented in the art for a means of addingstability to the table and for a fluid manifoldwhich could be used incooperation with the stabilizing means for supplying cooling or heatingfluid to the bottom mold parts. Ideally, the manifold would bepositioned at the center of the indexing table and provide rotarydistribution of the fluid to the plurality of bottom mold partsirrespective of their position on the periphery of the table.

SUMMARY OF THE INVENTION The present invention relates to injectionmolding machines and more particularly to an injection molding machinewith improved means for stabilizing the indexing table thereof and forsupplying fluid to a plurality of mold parts mounted on the periphery ofthe indexing table. y

In general, the present invention provides for a stationary verticalstandard which passes through a bore in the indexing table and for arotary fluid manifold which is in'par't keyed to the standard and-inpart mounted on the-table. The rotary manifold provides for rotarycirculation of fluid through the mold parts, irrespective'of theirradial position on the table. Further the manifold of the inventionpermits the vertical support standard to add stability to the indexingtable when high pressures are exerted on the outer periphery and at oneside thereof.

In accordance with a preferred embodiment of the manifold, a pair ofsleeves are concentrically positioned about the vertical supportstandard. An outer sleeve is mounted on the rotary indexing table forrotation therewith and an inner sleeve is keyed to the support standard.Separate axially spaced annular delivery and return passages are formedbetween the sleeves and cooperate with axially extending delivery andreturn bores in the inner sleeve and a plurality of outlets from thedelivery passage and a plurality of inlets to the return passage tocirculate fluid from an external source through the mold parts on thetable.

Packing rings are located at the upper and lower ends of the sleeves andseal the sleeves extemally, while O-rings seal the spaced passagesinternally. An effective axial pressure tight.

seal is formed across the ends of the respective sleeves by an annularmember at each end which has an inner radial portion for bearing againstthe inner sleeve and a radially extending flange portion for fasteningto the outer sleeve. Fastening means tighten the flange portion againstthe packing rings to complete the sealing thereof.

BRIEF DESCRlPTlON OF THE DRAWING FIG. 1 is a partially cut away sideelevation of a plastic injection machine having a rotary indexing tablecarrying a plurality of bottom mold parts around'the periphery thereofand showing in accordance with the'prese'nt invention a vertical supportstandard passing through a bore in the center of the table and a rotaryfluid manifold mounted onthe table about the standard;

FIG. 2 is across'sectional view of the rotary fluid manifold of thepresent invention; and

FIG. 3 is a top view of the manifold taken along line 3-3 in FIG. 2.

DETAILED DESCRIPTION OF 'THE PREFE RRED EMBODIMENT Referring to FIG. l,'a plastic injection molding machine 10 includes a base portion 11,a'central support portion 12, an indexing table assembly 13 supported bythe base and central support portions of the machine, and an overhangingbolster head 14. A horizontal plate 15 is supported by the base 1 1 andby angle struts 16, and a horizontal 'platfonn 17 is supported by thecentral's'upport portion 12 andby a vertical plate 18 connecting theplatform 17 with the plate 15.

The indexing table assembly 13 includes a flat plate 19 which supportsan automatic indexingmecha'nism 20. A vertical deflection support plate22 is positioned beneath the table under the head 14 and is supportedby'means24 (dotted lines) in the central support portion 14 of themachine. A rotatable indexing table 30 issupported on the top of theindexing mechanism and carries a plurality of peripherally spaced bottommold parts 35 with locating pins 36 extending upwardly therefrom.

The overhanging bolster head 14 supports a hydraulic fluid mechanism(not shown) to provide for the vertical reciprocation of an upper moldpart 40, and the reciprocating and mold locking arrangement maypreferably be made according to the teachings of the (1.8. Pat. ofTrueblood No. 3,309,739 issued Mar. 21', I967. The indexing mechanism'20 rotates the indexing table'in timed sequence so that a bottom moldpart is selectively rotated in position immediately below the upper moldpart 40. The upper mold part may thus be formed with a suitable recessor bore 41 for receiving the locating pin'36 on the bottom mold'part.This-position defines'the injection sta tion during which time the'uppermoldpart'40 is brought with high force into closing relation to thebottommold part 35 and an injection cylinder (not shown) moves axiallyforwardly and carries a nozzle which mates with cooperating nozzlesformed on the mold parts for injecting the mold cavity. The plasticizingcylinder and control arrangement may be constructed according to thePatent of Trueblood, 3,436,793 issued Apr. 8,

1969, and may include a hydraulically operated nozzle valve as shown inthat patent or a mechanically operated valve as shown in Trueblood, US.Pat. No. 3,172,161 of Mar. 9, i965.

During the mold closing and injecting step very high forces areestablishedt'en'ding to separate the mold parts 40 and 35 andcorrespondingly high closing forces must be maintained in order toprevent separation of the mold parts. The deflection plate 22 positionedimmediately below the injection station and below the indexing table 30absorbs a substantial portion of this high force. However, a'more rigidstructure may be maintained by the employment of a tension member, ineffect connecting the machine head 14 with the base 11. For this purposethe indexing table assembly 13 is provided with a vertical supportstandard or post '45 which is supported at its upper end on acantilevered plate 46 and which is supported at its lower end on thehorizontal plate 15. The plates 46 and 15 define respectively upper andlower support means for the post 45. The post 45 stands verticallythrough a bore 47 in the center of the table 30 and in non-interferringrelation with the molding operation. Suitable tightening nuts 48 areprovided to secure the post against rotation and to take up all of theplay.

The lower mold parts 35 are preferably formed as universal mold shoeswhich carry a chargeable die or insert. These mold parts are furtherprovided with fluid heating "or cooling passageway through which liquid,such as water, may pass for teaching-of Trueblood, US. Pat. No.3,091,809, issued June 4,

A rotary fluid manifold 50 is positioned on the table 30 concentricallyof the vertical support standard or post 45. Referring to FIG. 2, whichshows the manifold 50 in cross-section with the post 45 removed forclarity, a plurality of cylindrical spacers 52 are interposed between anannular ring 53 and the indexing table 30. The annular ring 53 supportsa tubular outer sleeve 55 and is integrally connected thereto by meansof a circumferential weld 56. A plurality of fastening bolts 57 passthrough appropriate bores 58 in the annular ring 53 and through thespacers 52 to secure the outer sleeve annular ring assembly to theindexing table 30 for rotation with the table.

The outer sleeve 55 has an inner cylindrical wall 59 having meansdefining a first annular delivery groove 60 and a second annular returngroove 61 axially spaced from the first groove, and further includes afirst circumferential enlarged notch or step 62 at the upper-end thereofand a second correspondingly enlarged circumferential notch or step 63at the lower end thereof. The sleeve55 is also provided with threecircumferential slots or grooves 65 between and on each side of theannular grooves 60 and 61. Resilient O-rings 66 are disposed within eachof the slots 65.

The manifold 50 further includes a non-rotating tubular inner sleeve 70which has a stepped outer surface defining a first, circumferentialradial shoulder 71, which is rotatably supported by an inner portion ofthe first circumferential notch 62 in the outer sleeve 55, and a secondcircumferential radial shoulder 72, the radial surface of which iscoincident with a portion of the second circumferential notch 63 in theouter sleeve 55. The outer surface of the sleeve 70 has a centralcylindrical portion 74 which extends between the shoulders 71 and 72 andmates against the inner wall 59 of the outer sleeve responding annularpassages between them. An axially aligned delivery bore 76 and anaxially aligned return bore 77 are formed in opposite radial sides ofthe upper axial face 79 of 1 to thereby define with the annular-grooves60 and 61 coradapted to be keyed into slots in the stationary verticalstandard 45 so that the inner sleeve 70 will remain fixed thereto.

As shown in FIGS. 2 and 3, the outer sleeve 55 has a plurality ofradially spaced outlets 88 leading from the delivery passage and acorresponding plurality of radially spaced inlets 89 opening into thereturn passage. As represented by-the dotted lines in FIG. 1, theseinlets and outlets are adapted to receive flexible delivery tubing 90and return tubing 91 which communicate the internal passages with theplurality of bottom mold parts 35 located around the periphery of theindexing table.

In the preferred embodiment of the rotary manifold, rotary packing meansare provided for the inner and outer sleeves at the ends thereof.Preferably, rotary packing rings 93 are positioned within the notch 62and the lower notch 63 in the outer sleeve 55,- and are held in positionby a pair of annular retainer ring members 95 which are L-shaped incross-sectional configuration. The annular members 95 have an innercylindrical portion 96 for bearing against the packing and a radiallyextending portion 97 having a plurality of bores therethrough forreceiving a plurality of fastening members 98 for tightening the membersagainst the packing rings 93 to compress them and complete the sealingthereof.

As shown in FIG. 2, a tubular bushing member 100 is interposed betweenthe inner sleeve 70 and the packing rings 93 in the lowercircumferential notch 63. The member 100 is secured to the inner sleeve70 by fastening pins 102 and is .wide enough to bridge the interfacebetween the sleeves. An

O-ring 104 forms a seal between the sleeve 70 .and the member 100. Itsupper end mates against the second shoulder 72 and against a portion ofthe notch 63, due to the coincidence of the shoulder 72 with the notch63. The inside surface of the annular member 95 bears against thebushing member 100.

In general operation, the outer sleeve 55 is first secured to vthe inletto the delivery bore 76 and the injection molding machine is started. Asthe indexing table 30 rotates, the outer sleeve 55 will rotate with itandthe first shoulder 71 will ride on the first notch 62, and theoutlets 88 and the inlets 89 will remain in opposed relation to theparticular bottom mold part 35 with which it is cooperating by way ofthe delivery tubing 90 and return tubing 91. Therefore, fluid willtravel to the mold part through the delivery tubing 90 by moving throughthe delivery bore 76 and its associated radial opening 81 to thedelivery passage 60 and out the appropriate radial outlet 88. in likemanner, fluid will leave the mold part by passing through the returntubing 91 to the return passage 61, and by traveling around the passage61 until it reaches the opening 83 to the return bore 77 from which itwill be removed from the assembly. I

The present invention accordingly provides a means of adding stabilityto the table and for offsetting the tendency of the table to deflectupon exertion of force by the upper mold part against the bottom moldpart, and at the same time provides a means of rotary circulation offluid through bottom mold parts irrespective of their position on theperiphery of the table. The stationary vertical standard and the rotaryfluid manifold effectively and efficiently cooperate with each other toprovide a simple and effective means of obtaining the results desired.

While the form of apparatus herein described constitutes a preferredembodiment of the invention, it is to be understood that the inventionis not limitedto this precise form of apparatus, and that changes may bemade therein withoutjdeparting from the scopeof the invention.

1 claim:

1. In an injection molding machine having a rotary indexing table forsupporting a plurality of mold parts thereabout and in which a verticalstandard extends through the table defining an axis about which thetable turns and forms a support structure for the molding machine, theimprovement in a rotary fluid manifold for applying heating and coolingfluids to the die parts supported on such table, comprising meansdefining an outer sleeve having an inside cylindrical opening extendingaxially therethrough, means mounting said outer sleeve on said table forrotation therewith with said standard extending through said opening,means in said outer sleeve at said cylindrical opening forming first andsecond axially spaced annular grooves, means in said outer sleevedefining passages leading into said grooves and providing connectionmeans by which heating and cooling fluids may be connected to such moldparts for flow therethrough, a tubular inner sleeve having an insidesurface mounted on and fixed to said standard and having an outercylindrical surface in mating engagement with the said insidecylindrical surface of said outer sleeve and closing bushing member 100and said annular grooves thereby defining corresponding first and secondannular flow passages between said sleeves, means in said sleevessealing said passages one from the other, and means in said inner sleevedefining an inlet passage leading into one of said annular passages andan outlet passage leading into the other of said annular passages bymeans of which such fluid may be applied to the die parts.

2. The improved manifold of claim 1 in which said inlet and outletpassages in said inner sleeve are axially positioned therein andterminate at an upper radial portion of said inner sleeve.

3. The improved manifold of claim 1 further comprising packing ringsadjustably mounted on said outer sleeve at the axial top and bottom endsthereof, and packing means interposed between said sleeves andengageable by said packing rings for forming a fluid-tight sealtherebetween.

4. In an injection molding machine having a rotary indexing table forsupporting a plurality of mold parts thereabout and in which a verticalstandard extends through the table defining an axis about which thetable turns and forms a support structure for the molding machine, theimprovement in a rotary fluid manifold for applying heating and coolingfluids to the die parts supported on such table, comprising meansdefining an outer sleeve having an inside cylindrical opening extendingaxially therethrough, means mounting said outer sleeve on said table forrotation therewith with said standard extending through said opening, atubular inner sleeve having an inside surface mounted on and fixed tosaid standard and having an outer cylindrical surface in close runningengagement with the said inside cylindrical surface of said outersleeve, means in said manifold defining first and second axially spacedannular flow passages between said sleeves, means in said sleevessealing said passages one from the other, means in said outer sleevedefining openings leading into said passages and providing connectionmeans by which heating and cooling fluids may be connected to such moldparts for flow therethrough, and means in said inner sleeve defining aninlet passage leading into one of said annular passages and an outletpassage leading into the other of said annular passages by means ofwhich such fluid may be applied to the die parts,

1. In an injection molding machine having a rotary indexing table forsupporting a plurality of mold parts thereabout and in which a verticalstandard extends through the table defining an axis about which thetable turns and forms a support structure for the molding machine, theimprovement in a rotary fluid manifold for applying heating and coolingfluids to the die parts supported on such table, comprising meansdefining an outer sleeve having an inside cylindrical opening extendingaxially therethrough, means mounting said outer sleeve on said table forrotation therewith with said standard extending through said opening,means in said outer sleeve at said cylindrical opening forming first andsecond axially spaced annular grooves, means in said outer sleevedefining passages leading into said grooves and providing connectionmeans by which heating and cooling fluids may be connected to such moldparts for flow therethrough, a tubular inner sleeve having an insidesurface mounted on and fixed to said standard and having an outercylindrical surface in mating engagement with the said insidecylindrical surface of said outer sleeve and closing said annulargrooves thereby defining corresponding first and second annular flowpassages between said sleeves, means in said sleeves sealing saidpassages one from the other, and means in said inner sleeve defining aninlet passage leading into one of said annular passages and an outletpassage leading into the other of said annular passages by means ofwhich such fluid may be applied to the die parts.
 2. The improvedmanifold of claim 1 in which said inlet and outlet passages in saidinner sleeve are axially positioned therein and terminate at an upperradial portion of said inner sleeve.
 3. The improved manifold of claim 1further comprising packing rings adjustably mounted on said outer sleeveat the axial top and bottom ends thereof, and packing means interposedbetween said sleeves and engageable by said packing rings for forming afluid-tight seal therebetween.
 4. In an injection molding machine havinga rotary indexing table for supporting a plurality of mold partsthereabout and in which a vertical standard extends through the tabledefining an axis about which the table turns and forms a supportstructure for the molding machine, the improvement in a rotary fluidmanifold for applying heating and cooling fluids to the die partssupported on such table, comprising means defining an outer sleevehaving an inside cylindrical opening extending axially therethrough,means mounting said outer sleeve on said table for rotation therewithwith said standard extending through said opening, a tubular innersleeve having an inside surface mounted on and fixed to said standardand having an outer cylindrical surface in close running engagement withthe said inside cylindrical surface of said outer sleeve, means in saidmanifold defining first and second axially spaced annular flow passagesbetween said sleeves, means in said sleeves sealing said passages onefrom the other, means in said outer sleeve defining openings leadinginto said passages and providing connection means by which heating andcooling fluids may be connected to such mold parts for flowtherethrough, and means in said inner sleeve defining an inlet passageleading into one of said annular passages and an outlet passage leadinginto the other of said annular passages by means of which such fluid maybe applied to the die parts.